// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_GFX_INTERPOLATED_TRANSFORM_H_
#define UI_GFX_INTERPOLATED_TRANSFORM_H_

#include "base/macros.h"
#include "base/memory/scoped_ptr.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/point3_f.h"
#include "ui/gfx/geometry/vector3d_f.h"
#include "ui/gfx/transform.h"
#include "ui/gfx/transform_util.h"

namespace ui {

///////////////////////////////////////////////////////////////////////////////
// class InterpolatedTransform
//
// Abstract base class for transforms that animate over time. These
// interpolated transforms can be combined to allow for more sophisticated
// animations. For example, you might combine a rotation of 90 degrees between
// times 0 and 1, with a scale from 1 to 0.3 between times 0 and 0.25 and a
// scale from 0.3 to 1 from between times 0.75 and 1.
//
///////////////////////////////////////////////////////////////////////////////
class GFX_EXPORT InterpolatedTransform {
public:
    InterpolatedTransform();
    // The interpolated transform varies only when t in (start_time, end_time).
    // If t <= start_time, Interpolate(t) will return the initial transform, and
    // if t >= end_time, Interpolate(t) will return the final transform.
    InterpolatedTransform(float start_time, float end_time);
    virtual ~InterpolatedTransform();

    // Returns the interpolated transform at time t. Note: not virtual.
    gfx::Transform Interpolate(float t) const;

    // The Intepolate ultimately returns the product of our transform at time t
    // and our child's transform at time t (if we have one).
    //
    // This function takes ownership of the passed InterpolatedTransform.
    void SetChild(InterpolatedTransform* child);

    // If the interpolated transform is reversed, Interpolate(t) will return
    // Interpolate(1 - t)
    void SetReversed(bool reversed) { reversed_ = reversed; }
    bool Reversed() const { return reversed_; }

protected:
    // Calculates the interpolated transform without considering our child.
    virtual gfx::Transform InterpolateButDoNotCompose(float t) const = 0;

    // If time in (start_time_, end_time_], this function linearly interpolates
    // between start_value and end_value.  More precisely it returns
    // (1 - t) * start_value + t * end_value where
    // t = (start_time_ - time) / (end_time_ - start_time_).
    // If time < start_time_ it returns start_value, and if time >= end_time_
    // it returns end_value.
    float ValueBetween(float time, float start_value, float end_value) const;

    float start_time() const { return start_time_; }
    float end_time() const { return end_time_; }

private:
    const float start_time_;
    const float end_time_;

    // The child transform. If you consider an interpolated transform as a
    // function of t. If, without a child, we are f(t), and our child is
    // g(t), then with a child we become f'(t) = f(t) * g(t). Using a child
    // transform, we can chain collections of transforms together.
    scoped_ptr<InterpolatedTransform> child_;

    bool reversed_;

    DISALLOW_COPY_AND_ASSIGN(InterpolatedTransform);
};

///////////////////////////////////////////////////////////////////////////////
// class InterpolatedRotation
//
// Represents an animated rotation.
//
///////////////////////////////////////////////////////////////////////////////
class GFX_EXPORT InterpolatedRotation : public InterpolatedTransform {
public:
    InterpolatedRotation(float start_degrees, float end_degrees);
    InterpolatedRotation(float start_degrees,
        float end_degrees,
        float start_time,
        float end_time);
    ~InterpolatedRotation() override;

protected:
    gfx::Transform InterpolateButDoNotCompose(float t) const override;

private:
    const float start_degrees_;
    const float end_degrees_;

    DISALLOW_COPY_AND_ASSIGN(InterpolatedRotation);
};

///////////////////////////////////////////////////////////////////////////////
// class InterpolatedAxisAngleRotation
//
// Represents an animated rotation.
//
///////////////////////////////////////////////////////////////////////////////
class GFX_EXPORT InterpolatedAxisAngleRotation : public InterpolatedTransform {
public:
    InterpolatedAxisAngleRotation(const gfx::Vector3dF& axis,
        float start_degrees,
        float end_degrees);
    InterpolatedAxisAngleRotation(const gfx::Vector3dF& axis,
        float start_degrees,
        float end_degrees,
        float start_time,
        float end_time);
    ~InterpolatedAxisAngleRotation() override;

protected:
    gfx::Transform InterpolateButDoNotCompose(float t) const override;

private:
    gfx::Vector3dF axis_;
    const float start_degrees_;
    const float end_degrees_;

    DISALLOW_COPY_AND_ASSIGN(InterpolatedAxisAngleRotation);
};

///////////////////////////////////////////////////////////////////////////////
// class InterpolatedScale
//
// Represents an animated scale.
//
///////////////////////////////////////////////////////////////////////////////
class GFX_EXPORT InterpolatedScale : public InterpolatedTransform {
public:
    InterpolatedScale(float start_scale, float end_scale);
    InterpolatedScale(float start_scale, float end_scale,
        float start_time, float end_time);
    InterpolatedScale(const gfx::Point3F& start_scale,
        const gfx::Point3F& end_scale);
    InterpolatedScale(const gfx::Point3F& start_scale,
        const gfx::Point3F& end_scale,
        float start_time,
        float end_time);
    ~InterpolatedScale() override;

protected:
    gfx::Transform InterpolateButDoNotCompose(float t) const override;

private:
    const gfx::Point3F start_scale_;
    const gfx::Point3F end_scale_;

    DISALLOW_COPY_AND_ASSIGN(InterpolatedScale);
};

class GFX_EXPORT InterpolatedTranslation : public InterpolatedTransform {
public:
    InterpolatedTranslation(const gfx::PointF& start_pos,
        const gfx::PointF& end_pos);
    InterpolatedTranslation(const gfx::PointF& start_pos,
        const gfx::PointF& end_pos,
        float start_time,
        float end_time);
    InterpolatedTranslation(const gfx::Point3F& start_pos,
        const gfx::Point3F& end_pos);
    InterpolatedTranslation(const gfx::Point3F& start_pos,
        const gfx::Point3F& end_pos,
        float start_time,
        float end_time);
    ~InterpolatedTranslation() override;

protected:
    gfx::Transform InterpolateButDoNotCompose(float t) const override;

private:
    const gfx::Point3F start_pos_;
    const gfx::Point3F end_pos_;

    DISALLOW_COPY_AND_ASSIGN(InterpolatedTranslation);
};

///////////////////////////////////////////////////////////////////////////////
// class InterpolatedConstantTransform
//
// Represents a transform that is constant over time. This is only useful when
// composed with other interpolated transforms.
//
// See InterpolatedTransformAboutPivot for an example of its usage.
//
///////////////////////////////////////////////////////////////////////////////
class GFX_EXPORT InterpolatedConstantTransform : public InterpolatedTransform {
public:
    explicit InterpolatedConstantTransform(const gfx::Transform& transform);
    ~InterpolatedConstantTransform() override;

protected:
    gfx::Transform InterpolateButDoNotCompose(float t) const override;

private:
    const gfx::Transform transform_;

    DISALLOW_COPY_AND_ASSIGN(InterpolatedConstantTransform);
};

///////////////////////////////////////////////////////////////////////////////
// class InterpolatedTransformAboutPivot
//
// Represents an animated transform with a transformed origin. Essentially,
// at each time, t, the interpolated transform is created by composing
// P * T * P^-1 where P is a constant transform to the new origin.
//
///////////////////////////////////////////////////////////////////////////////
class GFX_EXPORT InterpolatedTransformAboutPivot
    : public InterpolatedTransform {
public:
    // Takes ownership of the passed transform.
    InterpolatedTransformAboutPivot(const gfx::Point& pivot,
        InterpolatedTransform* transform);

    // Takes ownership of the passed transform.
    InterpolatedTransformAboutPivot(const gfx::Point& pivot,
        InterpolatedTransform* transform,
        float start_time,
        float end_time);
    ~InterpolatedTransformAboutPivot() override;

protected:
    gfx::Transform InterpolateButDoNotCompose(float t) const override;

private:
    void Init(const gfx::Point& pivot, InterpolatedTransform* transform);

    scoped_ptr<InterpolatedTransform> transform_;

    DISALLOW_COPY_AND_ASSIGN(InterpolatedTransformAboutPivot);
};

class GFX_EXPORT InterpolatedMatrixTransform : public InterpolatedTransform {
public:
    InterpolatedMatrixTransform(const gfx::Transform& start_transform,
        const gfx::Transform& end_transform);

    InterpolatedMatrixTransform(const gfx::Transform& start_transform,
        const gfx::Transform& end_transform,
        float start_time,
        float end_time);

    ~InterpolatedMatrixTransform() override;

protected:
    gfx::Transform InterpolateButDoNotCompose(float t) const override;

private:
    void Init(const gfx::Transform& start_transform,
        const gfx::Transform& end_transform);

    gfx::DecomposedTransform start_decomp_;
    gfx::DecomposedTransform end_decomp_;
};

} // namespace ui

#endif // UI_GFX_INTERPOLATED_TRANSFORM_H_
